1. Field of the Invention
This invention relates to a process of forming linear, branched, and/or cross-linked urethane-coupled polymers of quinone-coupled polyphenylene oxides which comprises contacting in a high fluid shear stress reaction medium a polyfunctional isocyanate with quinone-coupled polyphenylene oxide having an average hydroxyl group per molecule value greater than zero including 2.0 or less, and optionally, additionally, a polyphenylene oxide having an average hydroxyl group per molecule value greater than zero including 1.0 or less.